问题标题:
已知x>y>0,且xy=3,则(x^2+y^2)/(x-y)的最小值是
问题描述:
已知x>y>0,且xy=3,则(x^2+y^2)/(x-y)的最小值是
史雪梅回答:
(x^2+y^2)/(x-y)=[(x-y)^2+2xy]/(x-y)=(x-y)+6/(x-y)>=2√[(x-y)*6/(x-y)]=2√6
刘仲彬回答:
[(x-y)^2+2xy]/(x-y)=(x-y)+6/(x-y)为什么(x-y)^2变成了(x-y)?那个^2跑哪去了?
史雪梅回答:
[(x-y)^2+2xy]/(x-y)=(x-y)^2/(x-y)+2xy/(x-y)=(x-y)+6/(x-y)
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